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Develop measures of cyanotoxins and other algal toxins associated with ecological harm using aquatic test organisms
Citation:
Lazorchak, Jim, S. DeCelles, A. Kascak, W. Thoeny, N. Dugan, T. Sanan, Dan Tettenhorst, I. Struewing, AND J. Lu. Develop measures of cyanotoxins and other algal toxins associated with ecological harm using aquatic test organisms. 2021 SETAC North America Annual Meeting, Virtual, November 14 - 18, 2021.
Impact/Purpose:
This presentation will cover current status of assess the aquatic toxicity of toxins to standard laboratory test organisms.
Description:
There is a lack of information to estimate safe exposure levels for aquatic life to natural toxins produced by cyanobacteria and the freshwater invasive microalgae Prymnesium parvum. The uncertainty in concentrations and purity of standards for cyanotoxins, as well as their high cost, challenge their use for acute and chronic toxicity tests. An alternative approach was tested, using cultures of cyanobacteria and algae to generate toxins. In this study, we have developed laboratory cultures of toxin producers Microcystis aeruginosa UTEX B2666 (microcystin), Anabaena flos-aquae SAG 30.87 (anatoxin), Aphanizomenon flos-aquae PCC7905 (cylindrospermopsin), and Dolichospermum circinale CS-337 (saxitoxin) as well as non-toxin strain of A. flos-aquae and P. parvum UTEX 2797 (prymnesium). Tests were conducted with intracellular toxins obtained by removing cells from culture media and lysing them. Microcystins concentrations varied if only cell number and age of culture were tracked, with 1.75 X 106 cells/ml giving a microcystin concentration of 885 ug/L, while 4.16 X 106 cells/ml yielded 37 ug/L. Acute tests conducted with Ceriodaphnia dubia, Neocloeon triangulifer, Hyalella azteca, and larval Pimephales promelas using microcystins, did not cause any lethality different from the control at concentrations as high as 74 ug/L. However, the non-toxin-producing strain of A. flos-aquae caused mortality greater than the controls to N. triangulifer. For chronic tests IC25 for total microcystins for C. dubia, P. promelas, H. azteca, N. triangulifer were 8.9, 74.0, 408.9, and 10.1 ug/L, respectively. For P. parvum LC50s were 4.94 X 106 cells/ml for C. dubia and 1.22 X 106 cells/ml N. triangulifer. A method for measuring prymnesin is under development. Due to the variability in getting consistent intracellular toxin levels, an approach was taken to grow all of the 5 cyanobacteria cultures up to a stationary phase then test for toxin concentrations using ELISA methods. This was done in 250 ml cultures 3 times. Then cultures were increased to 4-liter volumes, then the isolated intracellular toxin was tested in a chronic format. Prymnesin was also tested in this same manner. Results of the culture methods used for all 5 of the cyanobacteria will be presented as well as the chronic or short-term growth results for microcystin, anatoxin, cylindrospermopsin, and saxitoxin.
